- Synthesis method of beta-damascenone
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The invention provides a synthesis method of beta-damascenone. The synthesis method comprises the following steps: 1) carrying out nucleophilic addition reaction on a compound II and acetylene to generate a compound III; (2) carrying out condensation reaction on the compound III and acetaldehyde to generate a compound IV, and (3) carrying out Meyer-Schureter rearrangement reaction on the compoundIV to obtain a compound V, namely the beta-damascenone.
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Paragraph 0054-0059
(2020/08/02)
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- An unexpected generation of magnetically separable Se/Fe3O4 for catalytic degradation of polyene contaminants with molecular oxygen
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Selenization of Fe2O3 with NaHSe led to Se/Fe3O4. The unexpected generation of Fe3O4 attributed to the reduction conditions of the reaction, and the resulted magnetic features of the materi
- Chen, Xingyu,Mao, Jingfei,Liu, Chuang,Chen, Chao,Cao, Hongen,Yu, Lei
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supporting information
p. 3205 - 3208
(2020/08/12)
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- Diastereoselective Synthesis of (±)-Epianastrephin, (±)-Anastrephin and Analogs Thereof
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A process for the synthesis of trans-fused γ-lactones having Formula (IV) from substituted cyclic ketones having Formula (I). A diastereoselective synthesis of (±)-epianastrephin (1) (wherein: R1 is ethenyl, R2 and R3 is methyl, and n is 1), (±)-anastrephin (2) (wherein: R2 is ethenyl, R1 and R3 is methyl and n is 1), and analogs thereof (wherein: R1 is H, C1-5 alkyl, C2-6 alkenyl or C2-6 alkynyl, R2 is H, C1-5 alkyl, C2-6 alkenyl or C2-6 alkynyl, R1 and R2 together with the carbon atom they are attached form a C3-6 cycloalkyl ring, R3 is C1-5 alkyl and n is 0-2):
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Paragraph 0090; 0091
(2017/11/14)
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- New application of cross-linked poly(N -bromoacrylamide) and poly(N -bromosuccinimide) as highly efficient and chemoselective heterogeneous polymeric catalysts for deprotection of 1,3-dithianes and 1,3-dithiolanes under mild conditions
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Cross-linked poly(N-bromoacrylamide) (PNBA) and poly(N- bromosuccinimide) as the mild and efficient heterogeneous polymeric catalysts were applied for selective deprotection of 1,3-dithianes and 1,3-dithiolanes to their corresponding carbonyl compounds. They were also effective as a reagent in aqueous media. These methods are very simple and the polymer catalysts could be recycled several times. Deprotection of thioacetal and thioketal without enolizable hydrogens proceeded very well to give only the corresponding aldehyde and ketone in high to excellent yield. Nevertheless, in the case of thioketals carrying enolizable hydrogens, deprotection accompanied with the formation of a minor ring-expanded product is observed. However, using the PNBA/H2O system, ring expansion of these thiolketals with enolizable hydrogen was not detected. These methods provide advantages, such as chemoselectivity, easy preparation, simple work up, excellent yields, and the ability to recycle the catalyst, which makes this method more useful compared to other known methodologies.
- Ebrahimzadeh, Farzaneh
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- Photocatalytic degradation of water taste and odour compounds in the presence of polyoxometalates and TiO2: Intermediates and degradation pathways
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Geosmin (GSM) and 2-methylisoborneol (MIB) are produced by several species of cyanobacteria and actinomycetes. These compounds can taint water and fish causing undesirable taste and odours. Studies have shown that GSM/MIB are resistant in standard water treatments. Polyoxometalates (POM) are efficient photocatalysts in the degradation and mineralization of a great variety of organic pollutants, presenting similar behaviour with the widely published titanium dioxide (TiO2). Photocatalytic degradation of GSM and MIB under UV-A light in the presence of a characteristic POM photocatalyst, SiW 12O404-, in aqueous solution has been studied and compared with the photodegradation by TiO2 suspensions. GSM and MIB are effectively degraded in the presence of both photocatalysts. Addition of OH radical scavengers (KBr and tertiary butyl alcohol, TBA) retards the photodegradation rates of both compounds, suggesting that photodegradation mechanism takes place via OH radicals. Intermediates identified using GC-MS in the case of GSM and MIB, are mainly identical in the presence of both photocatalysts, also suggesting a common reaction mechanism. Possible photocatalytic degradation pathway for both GSM and MIB is proposed.
- Fotiou, Theodora,Triantis, Theodoros M.,Kaloudis, Triantafyllos,Papaconstantinou, Elias,Hiskia, Anastasia
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- Synthesis of five-and six-membered 1,3,3-trimethyl-2-(trimethylsilyl) cycloalkenes: A novel preparation of alkyl/alkenyl/aryl 2,5,5-trimethyl-1- cyclopentenyl ketones
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1,3,3-trimethyl-2-(trimethylsilyl)cyclopentene and 1,3,3-trimethyl-2- -(trimethylsilyl)cyclohexene were prepared in good yields by the Wurtz-Fittig coupling reaction of the corresponding 2-iodo-1,3,3-trimethylcyclopentene and 2-chloro-1,3,3-trimethylcyclohexene with metallic sodium and chlorotrimethylsilane in anhydrous ether solvent. The Friedel-Crafts acylation reaction of 1,3,3-trimethyl-2-(trimethylsilyl)cyclopentene with six different acid chlorides and the novel preparation of six alkyl/alkenyl/aryl 2,5,5-trimethyl-1-cyclopentenyl ketones are reported.
- Venkatesha, Manjunatha A.,Suresh, Hariprasad
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p. 759-768+S57-S61
(2013/07/26)
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- Cabinet for locking a distributor and method
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A device for dispensing items comprises a cabinet having an interior for storing items. A dispenser frame is coupled to the cabinet and is configured to be accessed, such as by pulling the dispenser frame from the cabinet. The dispenser frame includes a plurality of dividers that are configured to hold the plurality of dispensing mechanisms that each hold multiple items within the storage area. Further, the dividers are reconfigurable to permit the arrangement of the dispensing mechanisms to be adjusted. A lockable door is coupled to the front of the cabinet in front of the dispenser frame. The door may be opened to provide access to the interior of the cabinet and to the dispenser frame. A dispense drawer is positioned below the storage area so that items dispensed from the dispensing mechanisms.
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- Total synthesis of (±)-dihydroactinidiolide using selenium-stabilized carbenium ion
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A new, short total synthesis of dihydroactinidiolide 1 is described using selenium carbenium ion-promoted carbon-carbon bond formation as the key step. Our synthetic strategy starts with a lactonization reaction between 1,3,3-trimethylcyclohexene 13 and α-chloro-α-phenylseleno ethyl acetate 14, affording the key intermediate, α-phenylseleno-γ-butyro lactone 15, which reacted via a selenoxide elimination to the target compound 1.
- Dabdoub, Miguel J.,Silveira, Claudio C.,Lenard?o, Eder J.,Guerrero Jr., Palimécio G.,Viana, Luiz H.,Kawasoko, Cristiane Y.,Baroni, Adriano C.M.
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scheme or table
p. 5569 - 5571
(2011/02/24)
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- Total synthesis of (±)-hedychenone: Trimethyldecalin terpene systems via stepwise allenoate diene cycloaddition
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(Diagram presented) The total synthesis of hedychenone 1 is described. The cycloaddition of the hindered diene 2 and the allenecarboxylate 3 has been shown conclusively to proceed via the [2+2] cycloadduct 5 to give a 2:1 mixture of the desired formal Diels-Alder adducts, the exo and endo isomers 4xn and is thus a stepwise [4+2] cycloaddition. The exo isomer 4x was converted in four steps (reduction, oxidation, olefination, and desilylation) into hedychenone 1.
- Jung, Michael E.,Murakami, Masayuki
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p. 5857 - 5859
(2007/10/03)
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- The catalytic enantioselective, protecting group-free total synthesis of (+)-dichroanone
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Herein we report the first enantioselective total synthesis of (+)-dichroanone, confirming the absolute configuration of the natural product. This protecting group-free route features the first application of our enantioselective Tsuji allylation in the context of a natural product total synthesis. Additionally, this 11-step preparation of the molecule from commercial material features a novel Kumada-aromatization strategy and a rapid sequence for the conversion of a phenol to a hydroxy-p-benzoquinone. Copyright
- McFadden, Ryan M.,Stoltz, Brian M.
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p. 7738 - 7739
(2007/10/03)
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- Investigations into the selective oxidation of vicinal diols to α-hydroxy ketones with the NaBrO3/NaHSO3 reagent: PH dependence, stoichiometry, substrates and origin of selectivity
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The NaBrO3/NaHSO3 reagent is one of the few oxidizing agents that chemoselectively oxidizes vicinal diols to α-hydroxy ketones with little overoxidation to the corresponding vicinal-dione or dicarboxylic acid. Oxidation reactions performed with this reagent showed strong pH dependence. cis-Vicinal diols reacted faster than trans-vicinal diols to the α-hydroxy ketone product. Hydroxy functional groups at axial ring positions were more readily oxidized than equatorial hydroxy groups. The application of the NaBrO3/NaHSO3 reagent for the chemoselective oxidation of vicinal diols was limited to simple systems and failed with more complex monosaccharide compounds probably due to acid catalyzed dehydrogenation reactions. Despite the simple reaction set-up and good selectivity towards the α-hydroxy ketone product, the actual oxidation reaction mechanism is highly complex and postulated to involve at least six different equilibria with a plethora of bromine containing species. A possible oxidation reaction mechanism is discussed.
- Bierenstiel, Matthias,D'Hondt, Paul J.,Schlaf, Marcel
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p. 4911 - 4917
(2007/10/03)
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- Method for synthesis of 2,2,6-trimethylcyclohexan-1-one
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The present invention relates to a method for synthesis of 2,2,6-trimethylcyclohexan-1-one (TMCH) by partial reduction of 2,6,6-trimethyl-2-cyclohexen-1,4-dione (ketoisophorone, KIP), the reaction being carried out in the gas phase in the presence of oxide catalysts.
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Page/Page column 3
(2008/06/13)
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- Sequential hydroformylation/aldol reactions: Versatile and controllable access to functionalised carbocycles from unsaturated carbonyl compounds
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Three different modes of hydroformylation/aldol reaction sequences involving either acid-catalysed aldol reactions, Mukaiyama aldol addition of pre-formed enolsilanes or aldol addition of in situ generated boron enolates can be applied to unsaturated ketones and ketoesters to afford the corresponding carbocyclic aldol adducts in good yields proceeding through the intermediate activated ketoaldehydes. In selected cases, complimentary, synthetically useful diastereoselectivities were observed in the products.
- Keraenen, Mark D.,Kot, Kinga,Hollmann, Christoph,Eilbracht, Peter
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p. 3379 - 3384
(2007/10/03)
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- Ozonolyses of 1-alkyl-substituted 1-tert-butylethylenes and highly methylated methylenecycloalkanes. The influence of the substituent steric bulk on the direction of cleavage of the primary ozonides
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Ozonolyses of 1-alkyl-substituted 1-tert-butylethylenes and of highly methylated methylenecycloalkanes were conducted in the presence of trifluoroacetophenone (7) in ether. The ozonolysis of 2,2,6-trimethyl-1-methylenecyclohexane provided only the crossed-ozonide 10 derived from capture of formaldehyde O-oxide with the ketone 7 in 42% yield, while in the case of the relevant 2,2,5-trimethyl-1-methylenecyclopentane the alternative crossed-ozonide 15e derived from cycloaddition of 2,2,5-trimethylcyclopentanone O-oxide with the ketone 7 was the sole isolable product. The total energies of two possible cycloreversion processes for the primary ozonide 12c and for 12e, calculated at B3LYP/6-31G**//B3LYP/3-21G* level of theory, seem to reproduce the observed difference in the regiochemistry of fragmentation between these two primary ozonides.
- Kawamura, Shin-Ichi,Yamakoshi, Hideyuki,Abe, Manabu,Masuyama, Araki,Nojima, Masatomo
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p. 891 - 896
(2007/10/03)
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- Identification of a precursor to naturally occurring β-damascenone
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9-Hydroxymegastigma-3,5-dien-7-yne 8a was synthesised and shown to be identical to an intermediate found in the acid-catalysed conversion of 3,5,9-trihydroxymegastigma-6,7-diene 4 to β-damascenone 1, 3-hydroxydamascone 5 and megastigma-5-en-7-yne-3,9-diol 6. When subjected to acid hydrolysis, 8a produced β-damascenone 1, in high yield. Importantly, the hydrolysate was completely free of 3-hydroxydamascone 5.
- Puglisi, Carolyn J,Elsey, Gordon M,Prager, Rolf H,Skouroumounis, George K,Sefton, Mark A
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p. 6937 - 6939
(2007/10/03)
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- α-Methylation of ketones via manganese-enolates: Absence of undesired polyalkylation
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The transmetalation of ketone lithium-enolates using MnBr2 generates manganese-enolates which react with CH3I to provide α-methylated ketones with essentially no undesired polyalkylated byproducts.
- Reetz, Manfred T.,Haning, Helmut
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p. 7395 - 7398
(2007/10/02)
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- The chemistry of thujone. XVI. Versatile and efficient routes to safronitrile, β-cyclogeranonitrile, β-cyclocitral, damascones, and their analogues
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Thujone, a waste by-product of the Canadian forest industry, has been utilized as a starting material to develop a versatile synthetic route to the damascones (rose oil ketones) and related analogues.The synthetic sequence provides a route to β-cyclocitral (45), the latter having been previously converted to β-damascone (2).In addition, thujone-drived intermediates are converted to β-damascenone (48) and to intermediates that can be utilized for the preparation of damascone analogues.In conjunction with the above, an efficient route to safronitrile (42), β-cyclogeranonitrile (43), and β-cyclocitral (45) from 2,6-dimethylcyclohexanone has been developed.In summary, these studies afford an attractive versatile route to these important perfumery materials.
- Kutney, James P.,Gunning, Philip J.,Clewley, Robin G.,Somerville, John,Rettig, Steven J.
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p. 2094 - 2114
(2007/10/02)
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- A synthesis of the abietane diterpenoid quinone (±)-royleanone via maleoylcobalt technology
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(±)-Royleanone has been synthesized by rapid construction of a highly substituted quinone using maleoylcobalt complex technology followed by acid induced cyclization of the corresponding hydroquinone methyl ether onto a tethered enone. The synthesis was completed by straightforward functional group manipulations.
- Liebeskind,Chidambaram,Nimkar,Liotta
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p. 3723 - 3726
(2007/10/02)
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- Regiochemistry of the Ring Expansion of Unsymmetrically Substituted Ketones involving β-Hydroxyalkylselenides
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β-hydroxyalkylselenides derived from unsymmetrically substituted ketones have been rearranged to substituted ketones in the presence of soft electrophiles such as silver tetrafluoroborate or dichlorocarbenes.Although the migration of the more substituted carbon often prevails, subtle variations have been observed depending upon the structure of the starting material and the experimental conditions used.
- Krief, A.,Laboureur, J. L.
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p. 1545 - 1548
(2007/10/02)
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- TRIENE CYCLIZATIONS. THE TOTAL SYNTHESIS OF PALLESCENSIN A.
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The total synthesis of pallescensin A has been achieved using a six ?, thermal electrocyclization reaction as the key step.
- Liotta, Dennis,Ott, Walter
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p. 1655 - 1666
(2007/10/02)
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- ALKYLATION DIRECTE DE CETONES ET D'ALDEHYDES EN PRESENCE DE POTASSE SOLIDE EN SUSPENSION
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Dehydrated solid KOH, suspended in aprotic solvents, is used as a base for ketone and aldehyde alkylation.The best solvent as regards yields and selectivity is DME.The quantity of KOH depends on the carbonyl compound acidity.This method gives as good results as less convenient homogeneous conditions.
- Artaud, I.,Torossian, G.,Viout, P.
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p. 5031 - 5038
(2007/10/02)
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- 208. Diastereoselektivitaet der Geruchswahrnehmung von Alkoholen der Iononreihe
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The characteristic odor of the diastereoisomers 1 and 2 of 1-(2,2,6-trimethylcyclohexyl)-3-hexanol is configuration dependent, the trans-alcohol 1 being identified as the sensorily active component.Structure modifications of model 1/2, for example substitution on C(2), C(13), and C(14) (ionon numbering) by CH3 groups, introduction of double bonds in the 3- or 4-position, and isosteric substitution of C(7) by an O-atom, leads to analogues revealing an unequivocal relation between stereochemistry and odor.The specific odor of alcohol 1 is generally released when all substituents are in an equatorial position; the resulting analogy with the molecular size and shape of odoriferous steroids suggests that the release of the particular scent can be correlated with a steroid-resembling receptor event.
- Schulte-Elte, Karl H.,Giersch, Wolfgang,Winter, Beat,Pamingle, Herve,Ohloff, Guenther
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p. 1961 - 1985
(2007/10/02)
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- THE WITTIG REACTION USING POTASSIUM-TERT-BUTOXIDE HIGH YIELD METHYLENATIONS OF STERICALLY HINDERED KETONES
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Potassium-tert-butoxide is recommended for general use in Wittig reactions with nonstabilized ylides.High yield methylenations of cyclohexanone and a series of five sterically hindered ketones demonstrate its utility.
- Fitjer, Lutz,Quabeck, Ulrike
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p. 855 - 864
(2007/10/02)
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- Removal of Thioacetal Protecting Groups by Benzeneseleninic Anhydride
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A number of thioacetals were deprotected with benzeneseleninic anhydride in good yield.The reaction worked particularly well for hindered spiro-1,3-dithiolans of 2,2,6-trimethylcyclohexanone and fenchone, and in examples where other literature methods had failed.
- Cussans, Nigel J.,Ley, Steven V.,Barton, Derek H. R.
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p. 1654 - 1657
(2007/10/02)
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- Effets de cryptands et activation de bases. VI. Reactions d'organo-lithiens.
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Utilization of the cryptand shows the need of electrophilic catalysis by the Li(1+) ion in the nucleophilic addition of organolithium compounds to ketones, esters, or carboxylic acids.When nucleophilic addition is inhibited, organolithium reagents enolyze ketones or esters.When activated by cryptation of Li(1+), organolithium reagents attack ethers in a few minutes.With alkyl halides, only elimination takes place: exchange and nucleophilic substitution are not observed any longer in the presence of the cryptand.Generally speaking, the cryptand seems to enhance the basicity of the organolithium reagent, and nucleophilicity does not manifest itself any more.
- Perraud, Robert,Handel, Henri,Pierre, Jean-Louis
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p. 283 - 288
(2007/10/02)
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- Fragmentierungsreaktionen an Carbonylverbindungen mit β-staendigen elektronegativen Substituenten, XXXIII 3-Oxatricyclo1,4>undec-4-en, ein stark gespannter Vierring-Enolether
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The behaviour of β-keto tosylates against nucleophiles has been investigated.The keto tosylate 6 underwent intramolecular cyclization with KOtBu in ether to produce exclusively the four-membered O-alkylated product 18 (the title compound).The substitution products 5 or 7 are obtained from 6 with NaOMe in methanol or KCN in DMSO, resp.Reaction of 6 with MeLi yielded the diol 13.The keto tosylate 31 reacted with MeLi analogously to form the diol 28, whereas with MeMgI a mixture of the Grob fragmentation product 33 and the alcohol 32 (via 28 by H2O elimination) was produced.Similarly keto tosylate 22b and MeMgI yielded the alcohol 27. - The non-enolizable keto tosylate 44 undergoes very slow reaction wih NaOH/MeOH to produce 41, 42, and 45 in low yield.
- Gerdes, Hero,Javeri, Shailaja,Marschall, Helga
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p. 1907 - 1920
(2007/10/02)
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